Kiewit Corporation, a Fortune 500 contracting company based in Omaha, filed the $400 million lawsuit in May

Receive the latest local updates in your inbox

Construction crews demolish a portion of the Mulholland Drive bridge above the 405 Freeway on September 29, 2012 in Los Angeles, California.

Updated at 1:14 PM PDT on Wednesday, Jul 2, 2014

The contracting company hired by the Metropolitan Transportation Authority to improve the 405 Freeway is suing the agency, alleging that Metro's actions led to massive delays and overspending on the $1 billion project.

Kiewit Corporation, a Fortune 500 contracting company based in Omaha, filed the $400 million lawsuit in May.

Kiewit was hired by Metro in 2009 to complete significant improvements to the 405 Freeway, most notably the addition of 10 miles of carpool lane between the 10 and 101 Freeways. The lane was officially opened in May, more than a year behind schedule and with overrun costs in the millions.

In 2011, the company was praised by then-mayor Antonio Villaraigosa for finishing construction ahead of schedule during the first "Carmageddon." They received a $300,000 bonus for their effort.

Among the bevy of claims made in the lawsuit are Metro's failure to negotiate with utility companies before construction began, causing delays and forcing multiple redesigns of structures like the Mulholland Drive bridge.

The contractor says the lawsuit was filed to drive Metro into agreeing to have Kiewit's claims evaluated by an independent dispute review board, a mediation device laid out in the company's original contract.

"We filed this complaint for the purposes to get Metro to follow the contract and participate in the process for all claims large and small," said Kiewit spokesman Bob Kula.

While the three-member board's rulings are not legally binding, they are admissible in court as evidence.

Kula said Kiewit wants to have the board make a recommendation that both the company and Metro could factor into their decision making.

Metro officials say Kiewit's claims are too broad to fit the contract provisions necessary for the dispute review board. Officials said in order for the issue to be brought up in front of the board, the company had to specifically identify what caused delays, along with the costs from the delays.

"Metro does not believe this claim complies with those contract requirements," officials said in a statement.

Previously, Metro officials blamed Kiewit for the collapse of retaining walls along the freeway, which a federal review found to be the largest contributor in the project being behind schedule.

Hearing dates for the lawsuit are still being decided.

Kula said the 405 Freeway Project, which to-date has spawned two "Carmageddons" and one "Jamzilla," will be done early this fall.